(3) has been already treated for belt and cotton rope. The
safe strength of the rope must meet the combined stress (i) 4-
(2) + (3), but the driving tensions Tn and /n caused by T will
both be decreased by the stresses (2) and (3).
Two shackles are shewn at Fig. 559. At A the wires are bent
back and soldered, giving a joint equal to the rope strength; but
B is wrapped round a wrought-irori eye and then spliced, the joint
having but 50 or 60 °/0 of the rope strength.
(9.) Pitch-chain Gearing serves the purpose of belting
where positive driving is required or considerable pressures
are to be transmitted. If high speeds are employed, the gear
should be exceptionally well made. Much power is lost in
friction, and the journals must be adjustable to take up stretch
Fig. 560 shews three forms of chain. At A the teeth bear on
solid inner links, but at B and c they engage with the pins, and
the smaller pitch obtained gives more regular driving. There are